title: Various randomized designs can be used to evaluate medical tests.
abstract: OBJECTIVE
  To explore designs for evaluating the prognostic and predictive value of medical tests and their effect on patient outcome.
  
  
  METHODS
  Theoretical analysis with examples from the medical literature.
  
  
  RESULTS
  For evaluating the prognostic value of a test, one can include the test at baseline in prognostic studies. To evaluate the value of test in predicting treatment outcome, the test results can be used as baseline information in randomized controlled trials of treatment. To compare the prognostic or predictive value of two or more tests, the test result combinations can be used as baseline information. To evaluate the effect on patient outcome, randomized controlled trials of test strategies are an option. Randomization can apply to all tested or be restricted to specific subgroups, such as those with discordant test results, to increase the efficiency of trials.
  
  
  CONCLUSIONS
  The prognostic and predictive value of medical tests can and should be evaluated, to demonstrate the test's ability to guide clinical decision making and to improve patient outcome. Various randomized designs can be used to evaluate the effects on testing on patient outcome.
authors.affiliation: Department Clinical Epidemiology & Biostatistics, Academic Medical Center, University of Amsterdam, Room J1b-214, PO Box 22700, 1100 DE Amsterdam, The Netherlands. Jeroen.lijmer@gmail.com
authors.forename: Jeroen G
authors.initials: JG
authors.lastname: Lijmer
authors.forename: Patrick M M
authors.initials: PM
authors.lastname: Bossuyt
mesh_terms: D019937:Diagnostic Techniques and Procedures / Q000592:standards*; D011237:Predictive Value of Tests; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012107:Research Design